The present invention relates to control systems in general and more particularly to an improved method for optimizing a controlled system parameter to obtain a maximum efficiency.
Methods of this general nature are known in the art. For example, one such method is described in the book "Statistical Analysis of Linear Control Systems" by W. Leonhard, 1973, pages 99 to 106. This known method superimposes a constant continuous test signal of smaller amplitude on the regulated variable. It performs a cross correlation of the test signal with the control system parameter which is to be optimized and uses the result of the correlation to drive an integrating control which then changes the regulated variable in a direction so as to cause the result of the correlation to become zero. The frequency of the test signal must be adapted to the time scale of the controlled signal. However, the formation of a mean necessary for performing the correlation must extend over a multiple of the period of the test signal. Because of this the prior art method for finding the optimum operating point is relative slow. In particular where the method is used in a controlled system having large time constants in its transfer function and rapid changes in its optimum operating point, as compared to that time constant, the objective of the system will not be reached.
In view of this, the need for an improved system of this general nature becomes evident.